High severity · published Aug 13, 2026
CVE-2026-70453
rsync < 3.5.0 Algorithmic Complexity DoS via hash_search()
7.5
CVSS
0.5%
EPSS
No
On KEV
Description
rsync before 3.5.0 contains an algorithmic complexity vulnerability in the hash_search() function that allows a remote attacker to cause a denial of service by delivering a carefully constructed file list. A sender can exploit the quadratic-time worst-case behavior in hash lookups to exhaust receiver CPU resources with a modest number of crafted entries, causing a sustained denial of service.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 44% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
RS
rsync · RsyncProject
through 3.4.4 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-70453
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-70453
github.com
https://github.com/RsyncProject/rsync/releases/tag/v3.5.0
github.com
https://github.com/RsyncProject/rsync/security/advisories/GHSA-8x5r-mjx8-83hv
www.vulncheck.com
https://www.vulncheck.com/advisories/rsync-algorithmic-complexity-dos-via-hash-search
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